Philosophy, as we see, necessarily co-evolved with religion and politics
in society. To survive, early symbolic philosophers rapidly learned to
focus on the dirty job of answering ``unanswerable questions'' that had
fallen through the cracks of the prevailing religion and hence didn't
provoke a short trip to a stake surrounded by highly flammable material
(or to an altar to have your heart ripped out, or to a prison cell where
you would die of disease and malnutrition forgotten by all other humans,
or...). Philosophers learned that religions didn't usually care about
geometry, for example, and that geometry was useful. It was also
fun to work on (for those people with the right kind of brain) and got a
lot of attention as a kind of ``truth'' that didn't seem to depend on
any particular things observed in one's sensory stream while still
seeming to describe many of them.

Occasionally a particularly brave or stupid philosopher would take a
stab at something more metaphysical (such as trying to invent an
explanation for what everything was made of) or humanistic (such as
working out social ethics on a ``rational'' basis). History contains
many examples of philosophers who discovered the hard way that this led
to a choice between voluntarily drinking hemlock or being burned at the
stake to protect common folk from your heretical views and as an example
to anyone foolish enough to believe that anything but the currently
accepted system of social ethics and religious memes was the right one
beyond question2.12.2

That is, to make a living at being a philosopher (and not get
killed), it was soon found to be necessary to invent new questions
that could actually be answered and that looked ``interesting'' in some
way. One had to do so while creating the illusion of answering,
or at least working on, the really hard ones, the big questions, all
without offending the local political power (usually a King) or
provoking the prevailing religious hierarchy by directly contradicting
scripture. Indeed, to be truly successful, it was often necessary to
have the active support of either the church or the crown if not
both, and there are numerous examples of philosophers who survived in
just that way.

As noted in the last chapter, logic and argument and rhetoric in general
doubtless coevolved with (spoken) language itself, but real human
language is pretty ambiguous and imprecise and arguments in it tend to
be sustained at the alehouse level. One of the greatest discoveries in
the history of humankind was that of the ``magic'' of algebraic
manipulation of symbols that permitted the abstraction of concepts
and relationships observed in and relevant to the ``real world''. As
key elements of this discovery, philosophers invented two very important
tools: Formal Logic and its more precise and abstract cousin,
Mathematics, along with written language.2.3

Mathematics and Logic were immediately useful, of course - bookkeeping,
monetary economics, the successful waging of war, the arguments of law,
the engineering demands of architecture and winning at a variety of
games of chance all relied on understanding and being able to manipulate
numbers and shapes and verbal arguments based on historical records to
guide future behavior. Some of the very earliest examples of written
language are basically bookkeeping records, and large armies (as opposed
to ``hordes'') have always required quantitative logistical planning to
transport and support in the field. Verbal argument was doubtless a
major component of successful business relationships and conflict
resolution, and required a way of determining valid sequences of
conditionally true statements as the argument was advanced to be
successful.

Thus it was that the card-carrying philosophers of antique and modern
times2.42.52.62.72.82.9
developed formal logic as the basis of a reasoning process
they could bring to bear on questions both deep and abstract and
immediately practical. Being (after all) clever, they also invented
schools where they could develop and pass on their own small
changes in the prevailing memetic schema directly to selected young
humans, bypassing a lot of potentially dangerous review by religion and
king - or better still educating the future priests and kings
themselves within their schools - and creating a long ``social
lifetime'' for their ideas. In this way new memes they invented
sometimes served as nucleation points that would grow and actually be
adopted by entire societies.

Formal logic (as will be discussed later) became a widely accepted
memetic schema for determining truth value or formulating powerful
arguments. It ws very simple and intuitive, but proved very powerful as
a basis for symbolic reasoning.

Much of the basis for formal logic can be found in the so-called Laws of Thought, which date back at least to the aforementioned
Parmenides, although the ones that we will study below are in a form
attributed to Aristotle, who wrote prolifically and whose writings (for
a variety of reasons) did a better than average job of surviving to
today.

Incidentally, Parmenides had some really good stuff in the few of his
writings to survive that were left out of Aristotle's Laws of Thought,
in particular a concept of the void not at all incompatible with
Zen's Mu (discussed below). This served as a precursor to concepts
(such as that of a vacuum) that eventually became Natural
Philosophy (in particular, Physics).

However, the language and world view of both Parmenides and Aristotle
were unsurprisingly hung up by the idea of time (a situation that
persisted until the last hundred years or so). Lacking a proper
understanding of space-time as a single geometry, verb tense
worked its way into the Laws of Thought where one would expect them to
be time-independent and sequence-independent. Even today, one of the
hardest things for students of physics to conceptually grasp is that in
a relativistic Universe, time ordering and sequence are not what their
classically trained perceptions tell them they are.

In fact, they are essentially classical laws in other senses as
well and are in many ways blind to the possibilities of non-classical
theories. As we will see, our notions of existence, causality, temporal
sequencing, inference and more rely on many axioms which are not objects about which one can reason using the laws of thought, and
which are, in fact, far from being ``obvious'' or ``self-evident truth''
the way they were for Aristotle.

Before we move on and examine the Laws of Thought, set theory, and logic
itself, it is worth noting that both India2.10 and
China2.11 were writing down theories of knowledge
and rules for inference that were roughly contemporary with those of the
Greeks. In both cases the actual rules very likely existed as oral
tradition long before they were written down. The Indian rules, in
particular, formed the basis for what might be called ``Buddhist Logic''
which is quite different from Aristotle's formal analysis of syllogism.
In particular it focuses less on ``proof'' and more on fallacies and on
ways of grading hypotheses. Its purpose seems to be the practical one
of using their ``logic'' (perhaps better called ``reason'') to teach, to
bring to the auditor of an argument conceptual or causal understanding
of the subject at hand2.12.